[GLLUG] How to repair an unallocated hard drive?

Chris Bell chrisbell at chrisbell.org.uk
Fri Jan 1 16:14:19 UTC 2021

Hello Mark
Knoppix appears to show sda as a 2TB disk partitioned using GPT which will 
install a GPT partition immediately after the space normally used by the DOS 
MBR to provide more space for information about multiple main partitions, not 
just the maximum of 4 physical partitions in the old MS-DOS. Most computers 
search for the MBR, so it is used to re-direct the BIOS to the GPT partition. 
The main boot sequence is then controlled from the GPT partition, and none of 
the other partitions will be labelled as bootable.
 I often see some unallocated space at either end of the disc space, usually 
less than 1 sector, but most of sda appears to be a single partition, possibly 
using a swap file instead of a swap partition.
Perhaps the disc was re-partitioned as a GPT disc, which would overwrite the 
original MS-DOS system, but then just left not further partitioned or 
There appears to be more information about sdb and its partitions without 
mention of corruption.
If sda is corrupted do not try to alter it. There was a package "photorec" 
designed to recover deleted photos which was later enhanced to recover almost 
anything and may be re-named "testdisk". It is not a quick and easy recovery, 
but can examine, list, recover, and copy as many directories and files as 
possible to another formatted disc.

Chris Bell

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